Blood Specimen Collection and Processing Venipuncture sampling Finger

Blood Specimen Collection and Processing • Venipuncture sampling • Finger stick sampling

Finger stick Procedure: 1. A phlebotomist must have a professional, courteous, and understanding manner in all contact with all patients. 2. Check the requisition form for requested tests, other patient information and any special draw requirements. Gather the tubes and supplies that you will need for the draw. 3. Position the patient in a chair, or sitting or lying on a bed. 4. Wash your hands.

5. The best locations for finger sticks are the 3 rd (middle) and 4 th (ring) fingers of the nondominant hand. Do not use the tip of the finger or the center of the finger. 6. Avoid the side of the finger where there is less soft tissue, where vessels and nerves are located, and where the bone is closer to the surface. 7. The 2 nd (index) finger tends to have thicker, callused skin. 8. The fifth finger tends to have less soft tissue overlying the bone.

10. When a site is selected, put on gloves, and cleanse the selected puncture area. 11. Massage the finger toward the selected site prior to the puncture. 12. Using a sterile safety lancet, make a skin puncture just off the center of the finger pad. The puncture should be made perpendicular to the ridges of the fingerprint so that the drop of blood does not run down the ridges. 13. Wipe away the first drop of blood, which tends to contain excess tissue fluid.

14. Collect drops of blood into the collection tube/device by gentle pressure on the finger. Avoid excessive pressure THAT CAUSE HEMOLYSIS 15. Cap, rotate and invert the collection device to mix the blood collected. 16. Have the patient hold a small gauze pad over the puncture site for a few minutes to stop the bleeding. 17. Dispose of contaminated materials/supplies in designated containers. 18. Label all appropriate tubes at the patient bedside

Hematocrit value PCV%

Haematocrite value (packed cell volume) Definition: % ratio of RBCs volume to total blood volume. Principle: specific gravity of RBCs 1090, plasma 1030, WBCs & platelets 1060.

Steps 1. Pinprick the thumb 2. Withdraw blood into the heparinized cappilary tube till ¾ th of its length 3. Close both ends of the tube with paste 4. Place the tube in the centrifuge for 5 minutes 5. Read the percentage of rbcs to blood volume

Blood withdraw

Apparatus heparinized cappilary tube (red mark)

plasma RBCS paste

Female sample

Male sample

What elements form the buff colored layer on the top of packed cells? v Specific gravity of WBCs = 1060 [form a thin layer (buffy coat) above RBCs. v Male < 43% v Female <36%

Clinical significance n Diagnosis of anemia, polycythemia. n To determine type of anemia calculate MCV & other blood indices. n WBCs & platelets are found above RBCs as thin buffy layer as they have more specific gravity than plasma & less than RBCs.

The conditions in which the HV varies from normal: A) The conditions in which PCV is increased: • Polycythemia: physiological (high altitudes or newly born) or pathological. • Dehydration (vomiting, diarrhea, profuse sweating) • Burns , loss of water , Hem concentration B) The conditions in which PCV is decreased: • Anemia • female, • hydration, • pregnancy(hemdilution)